In situ composites: effect of elongational flow velocity on thermotropic liquid crystalline co-polyester fibrillation in thermoplastic/TLCP systems

This study focuses on the TLCP fibrillation process in a thermoplastic (PP) matrix during melt blending. The process of blending includes a single ext rusion process in a twin-screw extruder with compatiblization and injection moulding of the extrudates. The TLCP, VA950 in situ fibrillation, compatib lization with PP and retainment of fibrils in the injection-moulded samples has already been achieved in our earlier study. However, the fibrillation process remains a complex issue. There are many factors like viscosity rati o, capillary number, composition, and flow speed which will affect the fibr illation. The elongational how seems to be a more important factor affectin g the TLCP fibrillation. The present study aims to identify the important f actors which influence the TLCP fibrillation at their near-critical conditi ons. The morphological features and mechanical properties show that the com patiblization and elongational flow speed are very important for effective fibrillation. (C) 2001 Elsevier Science Ltd. All rights reserved.